In the display panels such as the organic EL panel, currently it is difficult that a brightness characteristic is equalized over the whole areas, and generation of the uneven display becomes a serious problem. A fluctuation in film thickness of a light-emission layer in a display panel production process can be cited as an example of the cause for the generation of the uneven display.
In one of the conventional methods of correcting the uneven display, uneven display correction parameters for all the gradation levels are previously prepared in each pixel, and an input signal is corrected based on the uneven display correction parameter. In the above conventional method, it is necessary that the uneven display correction parameters for all the gradation levels are prepared in each pixel.
The inventor discovered that the fluctuation in threshold voltage (Vth) of a thin film transistor (TFT) in the organic EL panel causes the uneven display.
The invention notices that the fluctuation in threshold voltage of the thin film transistor (TFT) causes the uneven display. An object of the invention is to provide an uneven display correction method in which the uneven display is corrected to improve brightness evenness with the smaller number of parameters by correcting the input signal in order to modify the fluctuation in light-emission start gradation level among the pixels